As shown in FIG. 14, conventional oil feeders in tool holders of this type, have a stationary support member 3 which journals the rotary shaft 1 (for mounting from the spindle of a machine tool) for rotation in the member and removable coolant feeding passage connector to be discussed later, which can be attached to and removed from the coolant feeder on the machine tool. This permits coolant to flow through coolant feeding passage, to tools mounted in the rotary shaft. This feeds coolant to the oiling wheel of the tools through the coolant passage.
Since a coolant feeding passage is formed within the interface 8 between the stationary support member 3 at rest and the rotary shaft 1 in rotation, oil tight sealing rings 5 are disposed between the support member and the rotating shaft to prevent coolant leakage from the interface.
Over an extended period of service, cuttings and shavings can enter the mechanism and contaminate the coolant and thus become entrained between the oil tight sealing ring 5 and the circumferential rotating surface of the shaft 1 and dent or scratch the surface of the rotary shaft 5 as shown in a broken line H in FIG. 14. This breaks the oil tightness of the sealing rings and causes coolant leakage which can enter the bearings 2 along each side of the coolant feeding passage and can cause frequent accidents and damage to the bearings 2.
In the past, we attempted to prevent this problem by installing, as shown in FIG. 15, a replaceable sleeve 4 between the bearings 2 and between the rotary shaft 1 and the stationary support member 3, and to provide support for the oil tight rings 5.
Thus in the configuration shown in FIG. 15 when cuttings and shavings enter from the outside or contaminate the coolant enter between the oil tight sealing rings 5 and the surface of the sleeve 4 rotatably in contact with the sealing rings, the sleeve 4 had merely to be replaced without any need to replace the entire costly rotary shaft 1, thus reducing repairing costs by a considerable amount.
However, in our aforementioned improvement of the prior art, repair maintenance required to replace the sleeve 4 disassembly of the stationary support member 3 that is supported by bearings 2 and built integrally with the coolant passage connector, and reassembly to the original state when the sleeve 4 was replaced.